We all know that getting a great physique requires a long-term commitment.

But sometimes you want to tighten up your midsection and build a little extra muscle quickly, whether it’s before a weekend beach trip (think of the Insta pix), to impress an upcoming date once the clothes come off, or even to prep for an actual photo shoot where some skin will be showing. Or maybe you just want to jump-start your routine and put your training into overdrive.

Whatever your motivation, we’ve got the workout plan to get your body tight and lean—provided you’re already in decent shape—in only three days.

To make the magic happen, we consulted with Paul Vincent, an LA-based fitness trainer who’s worked with stars for movies like Star Wars: The Force Awakens and Blade Runner 2049. As a trainer to the stars, Vincent is often asked to help actors under the gun forge perfect celebrity bodies with little notice.

“Three days is a tough deadline to make significant change,” but it’s doable, says Vincent, who’s also the co-founder and CEO of Altus Sports Institute.

But overhauling your body quickly isn’t just about working out—you also have to focus on diet and sleep. “You’ll need to remove any inflammatory foods, or foods that make you bloat,” Vincent says. “Sleep is also incredibly important because it allows for the recovery of your adrenals and other important body systems. It’s easy to tell when people are well-rested, and it will contribute to looking good in a short amount of time.”

Note: When Vincent works with a new client, he suggests removing unhealthy foods and bad habits before adding anything. (“When you remove things,” he says, “there are far fewer dangers.”) Remember to be careful when making any drastic changes to your diet or exercise. Consult with your doctor before trying a whole new approach like this three-day body blitz.

Step 1: Focus on your food

Nutrition is the cornerstone of a great-looking body. “Exercise does not compensate for a bad diet,” says Vincent. Nutrition affects all your systems and organs, so nourishing your body with whole, real foods is paramount. “Proper nutrition doesn’t need to involve complicated recipes,” he says. “Choose nutritious snacks like almonds, or fresh fruits like grapes or apples, throughout this three-day process to help you create positive changes.”

Step 2: Start to prioritize your sleep

If you don’t get enough restful sleep, you can set yourself up for negative health consequences like prematurely aged skin, diabetes, obesity, and heart disease. Sleep deprivation messes up the body’s endocrine system, which regulates appetite and blood sugar. Plus, sleep clears away neurotoxic waste that builds up in the nervous system during the day, and it’s when your body goes to work rebuilding the muscle you damaged by exercising.

“To get good sleep, you need to separate yourself from your electronics,” Vincent says. “Turn them off an hour before bed so you can mentally wind down and avoid the blue light the devices produce.” Studies have shown that blue light signals the brain that it is daytime, disrupting our circadian rhythms and impacting sleep.

“Another tip is to ensure your room is quiet, dark, and cool,” he says. “You don’t want your room to be too warm—studies have actually shown that people sleep better in cooler rooms.” Try avoiding caffeine in the afternoon. And once you lay down at night, do 15 minutes of diaphragmatic breathing—or deep breathing, during which you inhale through your nose and it makes your stomach protrude—to help calm your body down and transition into sleep.

Step 3: Work out your body the right way

“A lot of people misunderstand the purpose of exercise,” says Vincent. The objective is to challenge your body, because by challenging your bodily systems, they become stronger. “For example: When you challenge the cardiorespiratory system, it adapts to meet that stress. As it adapts, the system will become more and more efficient, meaning you will become fitter and fitter.”

Your goal in this three-day plan is to burn calories and challenge your body as much as possible. “Since you only have three days, you’ll need to focus on switching up your training throughout your accelerated workout plan,” he says. “In my company, we switch the way we train people every few weeks so they’re challenged in many different ways throughout the year. Do everything you can to challenge your body in the three days you have. It can be going for a walk at lunch or doing some pushups on your office floor—just keep moving your body.”

The workout

This workout plan includes cardio and high-intensity interval training to get your heart rate up and your circulation going, and some strength work to pump-up your muscles.

“Often, with actors, I get a very short window to get them the look they need,” says Vincent. “For a quick transformation, working out multiple times per day will help.”

Again, make sure you talk to your doctor before jumping into an intense workout routine.

On Day 1, start your afternoon gym workout with a treadmill warmup. Power walk at 4.0 for 2 minutes, run at 6.0 for 2 minutes. Alternate 4.0 and 6.0 for 2 minutes each for a total of 20 minutes.

On Day 2, start your afternoon gym workout with a warmup on the stationary bike. Begin riding at level 6 for 10 minutes at 120 rpm, then increase intensity level to 10 for 5 minutes at 100 rpm, followed by a “cooldown” at level 4 for 5 minutes at 80 rpm.